2. You don't even look pregnant!
This may seem like a compliment to some, but being told you don't look pregnant takes away the pride and hard work she's already put into growing a new human. Chances are she feels pregnant, so don't detract from this but saying that little bump she's so excited to see doesn't count.

On the same token, telling her she looks like you do when you eat a burrito isn't as funny as you might think...